Draft: Decoupling red data classification and tier 1 critical system tier

Why is this change being made?

Historically, the storage and processing of red data was done within systems that if they experienced an outage, the GitLab platform and it's users (including customers) would be affected. Therefore, we made the decision to couple the red data classification with Tier 1. As the company has grown, we've introduced systems that store and process red data that would not affect the platform if an outage occurred (e.g., Devo, Snowflake, OpenAI).

The focus of our Critical System Tiering methodology is availability and the affect of outages to the achievement of our mission and business objectives. To ensure the Tier 1 Mission Critical systems reflect systems where a disruption has an immediate and significant impact to the availability of GitLab subscriptions, we are decoupling Red Data with Tier 1 Mission Critical. This creates greater differentiation, prioritization, and clarity for related systems.

Reducing the overlap of methodologies, standards, and scopes creates greater transparency and allows differentiation/prioritization based on the context of each system.

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
  • Copy/paste the Slack conversation to document it for later, or upload screenshots. Verify that no confidential data is added, and the content is SAFE
• Assign reviewers for this MR to the correct Directly Responsible Individual/s (DRI)
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the Maintained by section on the page being edited
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies
  • The when to get approval handbook section explains the workflow in more detail
• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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